While formula may be able to mimic the nutritional value, it can’t match breast milk in protecting babies from illness, nor is it as easily digestible by the newborn’s immature digestive tract. Epidemiological studies have shown that breastfed babies have fewer bouts with ear infection, respiratory infection, meningitis, diarrhea, and constipation. They also have lower risk of allergies, asthma, obesity, diabetes, childhood leukemia and sudden infant death.

The benefits to mothers are similarly impressive, with studies linking breastfeeding to lower risk for type 2 diabetes, breast cancer, ovarian cancer, hypertension, cardiovascular disease, and postpartum depression. The skin-to-skin contact with their babies causes the mother’s pituitary to release oxytocin, a hormone that helps milk flow, while at the same time helping the uterus to shrink after delivery.

From a purely practical standpoint, breast milk is always available, does not have to be warmed before feeding the infant and does not require lugging around a bunch of supplies. Also, breast milk is free and breastfeeding saves the cost of formula and supplies, which can tally up to more than $1,500 a year. Breastfed babies have been shown to be sick less often, resulting in lower health care costs and fewer missed days of work for parents. The government estimates the U.S. could save $13 billion a year in medical care costs if 90 percent of new mothers breastfed exclusively for six months.